Double belt freezing machine

ABSTRACT

A double belt freezing machine has a pair of thermally conducting belts trained around drums mounted on a frame so that the horizontal upper run of the lower belt and the horizontal lower run of the upper belt are spaced apart a distance adjustable by moving a carriage on which the upper belt is mounted up and down on the frame. In thermal contact with the belts are platens joined to a refrigerating system at least in part mounted on the frame, the upper platen having flexible connections thereto. Foodstuffs such as hamburger patties are fed between and in thermal contact with the adjacent runs of the belts and emerge frozen.

O l United States Patent [1 1 [111 3,791,162 Baker Feb. 12, 1974 DOUBLE BELT FREEZING MACHINE Primary Examiner-Meyer Perlin Assistant Examiner-Ronald C. Capossela [75] Inventor. Edward D. Baker, Belmont, Cal1f. Attorney, g or Firm Lothrop & west [73] Assignee: NPI Corporation, Burlingame, Calif. [22] Filed. July 13, 1972 ABSTRACT [2]] Appl. No.: 271,247

A double belt freezing machine has a pair of thermally conducting belts trained around drums mounted on a [52] US. Cl 62/341, 62/380, 100/93 RP frame so that the horizontal upper run of the 1ower [51] Int. Cl. F 25c 5/14 belt and the horizontal lower run of the upper belt are [58] Field of Search 62/63, 341, 345, 380; spaced apart a distance adjustable by moving a can 100/93 RP riage on which the upper belt is mounted up and down on the frame. In thermal contact with the belts are [56] References Cited platens joined to a refrigerating system at least in part UNITED STATES PATENTS mounted on the frame, the upper platen having flexi- 3,300,994 1/1967 Bagge-Lunde 62/34] x ble connections thereto- Foodstuffs Such as hamburger 3,378,430 4/1968 Aizawa 100/93 RP x patties are fed between and in thermal contact with 2,133,348 10/1938 Ferenci 62/341 X the adjacent runs of the belts and emerge frozen. 2,800,162 7/1957 Rohclin 100/93 RP 4 Claims, 6 Drawing Figures PATENTED fun 2 1914 SHEET 1 0F PATENIEDFEB 12 I974 SHEU 2 [1F 4 mango FEB 1 2 1914 saw 3 or 4 DOUBLE BELT FREEZING MACHINE There is an increasing need for machines for preconditioning foods for further processing and particularly for machines that will operate continuously on a large quantity of foods. More particularly, there is a requirement for freezing hamburger patties in continuous array so that a large amount of product can be continuously conditioned for storage prior to subsequent cooking. Somewhat related to this class of machines is a machine for cooking food products as shown in the patent to Norris 3,646,880 issued Mar. 7, 1972. In the present instance the machine is not involved with the cooking sequence but rather is involved with preconditioning foodstuffs for storage and usually, although not necessarily, prior to cooking, The preferred procedure, as an example, is to start with a foodstuff, such as hamburger or comparable ground meat, and subject it to freezing. It is desirable to remove the ordinary (room temperature) heat as quickly as possible and in an economical fashion. While it is customary to subject the product, such as meat, to a draft or blast of cooling gas such as low temperature air, this requires the use of air blowing and circulating fans which actually heat the air. Some of the refrigerating effect is immediately lost. I prefer to use a direct contact heat transfer arrangement so that there is little loss in transferring the heat out of the meat and the arrangement is, therefore, economical. Also, since the meat has some water content, the initial heat extraction causes some ice to form. While in some respects this may appear to be a disadvantage, it does provide an extensive and intimate contact surface for rapid heat transfer. Any other films or surfaces between the foodstuff and the heat sink or refrigerant are few in number and are kept thin and are in firm contact so that heat travel therethrough is hindered as little as possible. Even surfaces moving relative to each other and in close contact have very low friction so as to develop only small amounts of heat. The net result is to provide in an economical, simple fashion a quick freezing arrangement affording relatively low food temperatures (around minus 35 F. about as fast as can be attained with cryogenic gases but with the use of ordinary economial regrigerants.

It is therefore an object'of my invention to provide a freezing-machine that will operate continuously'on' products such as hamburger patties, taking them in in natural condition and discharging them in frozen condition.

Another object of the invention is to provide a machine which will operate continuously over a long period of time without difficulty and with substantially uniform results.

Another object of the invention is to provide a machine which while freezing the patties or like materials is also effective to size them to a substantially uniform thickness.

Another object of the invention is to provide such a machine with the ability to accept items such as hamburger patties readily and to discharge them without sticking or disruption of the operation of the device.

Another object of the invention is to provide a freezing machine that is easy to maintain in a sanitary condition.

A further object of the invention is to provide a freezing machine that readily can be adapted to refrigeration equipment presently available.

A still further object of the invention is to provide a freezing machine that in general is a substantial improvement over freezing machines heretofore available.

Other objects, together with the foregoing, are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIG. 1 is a side elevation of a double belt freezing machine constructed in accordance with the invention;

FIG. 2 is a plan of the machine shown in FIG. 1;

FIG. 3 is a cross-section, the plane of which is indicated by the line 3-3 of FIG. 1;

FIG. 4 is a cross-section, the plane of which is indicated by the line 44 of FIG. 2;

FIG. 5 is a fragmentary showing in cross-section, the plane of which is indicated by the line 55 of FIG. 1;

- and FIG. 6 is a fragmentary view in cross-section, the plane of which is indicated by the line 6-6 of FIG. 1.

While the double belt freezing machine pursuant to the invention can easily be incorporated in a large number of different ways, it has with success been incorporated in the form disclosed herein. I

In this arrangement there is provided a frame 6 comprised of a number of legs and connecting members secured together in the usual way to afford a generally rectangular framework adapted to rest on the floor and to serve as a support and attachment for the remaining parts of the structure.

Extending between the legs of the framework are side rails 7. Just above the rails are frame members 8 and 9 secured to the legs and established at substantially a standard height. There are two frame extensions 8 at one end of the machine and a similar pair of frame extensions 9 at the other end of the machine. The frame extensions 8 support a cross shaft 10 with a belt drum 11 secured thereto, the shaft 10 being mounted in adjustable bearing blocks 12 having a position control 13 associated therewith. Similarly, the frame extensions 9 support a shaft 16 having a drum 17 associated therewith. The shaft 16 is similarly supported in bearing blockslS having a position adjustment 19 associated therewith. v

Trained around the drums ll 1 and 17 is a freezing belt 21 which preferably is endless and is conveniently fabricated of material such asnylon mesh. The material of the belt is not particularly adhesive to any of the food products that may come into. contact therewith and is not adhesive with respect to the surface of the drums .11 and 17. Preferably, it is of a solid fiber so as not readily to be impregnated with any of the materials being conveyed. It preferably has spaces between the threads of the weave to assist in the conduct of heat. Such a fabric belt is referred to herein as a thermally conducting belt. It is not as conductive as a metal belt but is effective, because of its construction, to serve reasonably well as a heat transferring medium. The belt 21 has its upper run 22 in substantially a horizontal position at a given height and the return or lower run 23 is somewhat below the selected height.

In accordance with the invention, there is provided on the framework 6 a carriage, generally designated 26 or elevator. As particularly shown in FIG. 2, the carriage 26 includes two pairs of guide members 27, one pair at each end, the guide members running close to the various legs of the frame 6 so that the carriage is guided in a rectilinear path for up and down movement. The pair of guides 27 at one end of the machine has a pair of extensions 28 carrying a cross shaft 29 on which a drum 30 is disposed. The ends of the shaft 29 are supported in bearing blocks 31 having adjustments 32. Similarly, the guides 27 at the opposite end of the machine ride around or are guided by the adjacent legs of the framework 6 and thenselves have extensions 33 in which bearing blocks 34 are mounted. The bearing blocks have adjustments 35 in order to position a cross shaft 36 on which a drum 37 is mounted. An upper conveyor belt 38 is trained around the drums 30 and 37, having its upper run 39 at a predetermined elevation and having its lower run 40 in a plane parallel to the adjacent upper run 22 of the lower belt. Preferably, the adjustments are such that the belts operate with a fair degree of tautness so that at least the adjacent runs approximate planar members.

In order to adjust the position of the upper belt and so adjust the space between the upper belt and the lower belt, means are provided for positioning the carriage at an established or selected elevation. Adjacent one of the frame legs 6 there is provided a hand crank 41 effective to rotate an adjusting shaft 41 journalled in an adjacent pair of the frame legs 6. There is a sprocket 43 on one end of the shaft 42 engaged with a chain 44 which also engages a sprocket 46 mounted on a shaft 47 journalled in the pair of frame legs 6 at the opposite end of the machine so that when the hand crank 41 is rotated, both of the sprockets 43 and 46 are rotated in unison and in the same direction.

As particularly illustrated in FIG. 5, there is wound on the shaft 42 a pair of cords 51 at one end of the machine. Each of the cords extends from the shaft 42, serving as a winch drum, vertically over an idler pulley 52 journalled in the upper portion of an adjacent frame leg 6 and finally terminating on a rod 53 projecting from the adjacent one of the guides 27 through an accommodating slot 54 in the flange of the adjacent frame leg 6.

Similarly, the shaft 47 likewise is provided with a pair of cords 56 extending over idlers 57 on the adjacent ones of the frame legs 6 and then depending to be fastened to a respective one of a pair of rods 58 extending through an accommodating slot 59 in the adjacent leg and fastened to the guide 27. Since the various cords are made of substantially the same length, the four corners of the carriage are supported substantially horizontally and at any elevation set by the position of the crank 41 so that the spacing between the lower run of the upper belt and the upper run of the lower belt is established at a value desired.

In order that product heat may be transmitted through the belts and can be taken away for disposal elsewhere, 1 preferably provide refrigerant tanks 61 and 62 on the frame, preferably above the carriage. The tanks 61 and 62 may be connected by any suitable means, not shown, to a refrigerating plant so that the tanks 61 and 62 can contain a liquid refrigerant in the lower portion thereof and can also contain a gaseous refrigerant in the upper portion thereof. While the tanks can be separate, they are sometimes provided with an interconnecting pipe 63 under the control of a hand valve 64 so that they can be utilized individually or separately.

The tank 61, for example, has an outlet connection 66 extending through a flexible conduit 67 to a fitting 68 to one end of an upper platen 69. This platen preferably is of conducting metal and includes a pair of manifolds 71 and 72 spaced apart by an intervening, thermally conducting plate 73 supporting a plurality of refrigerant bores 74 in the plate and extending between the manifolds. Refrigerant received in the manifold 71, for example, can travel through the bores 74 and emerge into the maifold 72, from which flow can occur through a fitting 75 and a conduit 76 back to a connecting pipe 77 at the upper end of the tank 61. In this fashion there can be a circulation of refrigerant through the upper platen 69. The platens are conveniently arranged in pairs and are removably supported on the carriage by clips and brackets 80.

Comparably, the tank 62 has an .outlet fitting 78 connected to a flexible conduit 79 extending to a manifold 81 at one end of a platen 82 including a thermally conducting plate 83 having a plurality of bores 86 extending therethrough. from the maifold 81 to a second manifold 87. From the mainfold 87 a fitting 88 is joined to a pipe 89 extending to a duct 91 at the upper portion of the tank 62. In this fashion circulation from the tank 62 is through the lower platen, specifically through the bores 86 thereof, and then back to the upper part of the tank 62. In this fashion both of the platens are maintained at the desired low temperature.

The upper belt is arranged so that its lower run 40 moves in very close contact with the platen 69. Conveniently, both beltsare generally of uniform thickness in cross-section but have a marginal bead 92 along one side and a comparable marginal bead 93 along the other side. In order to accommodate such heads, the plate 73 and the plate 82 are offset slightly from their manifolds so that the main body of the belt is in close sliding engagement with the plate, but the beads 92 and 93 are free of the adjacent manifold mechanism.

In a comparable fashion, the upper run of the lower belt likewise slides over the top of the plate 83 in close thermal contact therewith. The interconnection between the plate and the manifolds 81 and 87 is such that the beads 94 and 96 near the edges of the lower belt are afforded adequate clearance and are not effective to space the belt web from immediate contact with the platen. Since the belts are of nylon and it is convenient to make the platens of aluminum, there is very little sliding friction an heat developed between the belts and the platens.

In the operation of the device after the crank 41 has been set to position the platens as far apart as is desired, and after the refrigerant has been circulated through the platens for a length of time sufficient to lower their temperature to the desired value, an opera-' tor places foodstuffs such as hamburger patties on the upper run of the lower belt; for example, at the righthand end of the machine. The lower belt extends outwardly from the machine a substantial distance to make a sort of table to receive the products deposited thereon. The deposited products are advanced into the machine since the belts are appropriately driven. On the framework there is supported an electric motor 101 driving a chain 102 which is trained around a sprocket 103 at one end of the shaft 10 and around a similar sprocket 104 at the adjacent end of the shaft 29, thence around an idler sprocket 106 at the lower end of a lever 107 having a pivot connection 108 to the framework and being under the urgency of a spring 109. The chain 102 is thus kept taut and drives the sprockets 103 and 104 at the same speed but in opposite directions. Materials deposited, therefore, on the upper run of the lower belt are advanced between the belts from right to left in FIG. 1. If the deposited product is substantially thicker than the set space between the adjacent portions of the two belts, the product is deformed and flattened or thinned until it can easily travel through the machine in close thermal contact with the adjacent belts. -As it travels through the machine, the material is able to give up its heat to the adjacent platens and eventually is reduced to the desired low temperature, whereupon it appears between the rollers 11 and 30 at the left-hand end of the machine on a sort of table there formed by the shortened upper run of the conveyor.

With this arrangement, the machine once having been put into operation, it is possible to feed in products at the entrance end, to have them move continuously through the machine in any desired quantities, and to have them discharged at the far end of the machine at a reduced temperature suitable for storage or for subsequent operation.

What is claimed is:

1. A double belt freezing machine comprising a framework, a first freezing platen stationarily mounted on said framework in a horizontal plane, a first freezing belt having a lower run and an upper run, means for mounting said first freezing belt on said framework for advancement of said upper run thereof in contact with the top of said first freezing platen, an elevator, means mounting said elevator on said framework for selective movement up and down to selected fixed distances from said first platen, a second freezing platen stationarily mounted on said elevator in a horizontal plane and in vertical registry with said first freezing platen, a second freezing belt having a lower run and an upper run, means mounting said second freezing belt on said elevator for advancement with said lower run and in contact with the bottom of said second freezing platen, a refrigerant reservoir, me ans mounting said refrigerant reservoir on said framework, and means including conduits connecting said refrigerant reservoir to said first freezing platen and said second freezing platen for cooling the same, said belts being of heat conductive material and each being of a lateral width to extend substantially completely across its respective platen.

2. A machine as in claim 1 in which said first freezing platen and said second freezing platen each includes a refrigerant supply manifold along one side, a refrigerant exhaust manifold along the opposite side, means defining a plurality of transversely extending refrigerant passages, through the platen, connecting said manifolds, said manifolds and said defining means being at different elevations to accommodate freezing belts of variable thickness in cross-section in contact with said platens and adjacent said manifolds.

3. A machine as in claim 1 in which said reservoir has individual tanks and said connecting means joins one of said tanks to said first freezing platen and joins another of said tanks to said second freezing platen.

4. A machine as in claim 1 in which said conduits connecting said refrigerant reservoir to said second freezing platen are flexible.

* =l= II 

1. A double belt freezing machine comprising a framework, a first freezing platen stationarily mounted on said framework in a horizontal plane, a first freezing belt having a lower run and an upper run, means for mounting said first freezing belt on said framework for advancement of said upper run thereof in contact with the top of said first freezing platen, an elevator, means mounting said elevator on said framework for selective movement up and down to selected fixed distances from said first platen, a second freezing platen stationarily mounted on said elevator in a horizontal plane and in vertical registry with said first freezing platen, a second freezing belt having a lower run and an upper run, means mounting said second freezing belt on said elevator for advancement with said lower run and in contact with the bottom of said second freezing platen, a refrigerant reservoir, means mounting said refrigerant reservoir on said framework, and means including conduits connecting said refrigerant reservoir to said first freezing platen and said second freezing platen for cooling the same, said belts being of heat conductive material and each being of a lateral width to extend substantially completely across its respective platen.
 2. A machine as in claim 1 in which said first freezing platen and said second freezing platen each includes a refrigerant supply manifold along one side, a refrigerant exhaust manifold along the opposite side, means defining a plurality of transversely extending refrigerant passages, through the platen, connecting said manifolds, said manifolds and said defining means being at different elevations to accommodate freezing belts of variable thickness in cross-section in contact with said platens and adjacent said manifolds.
 3. A machine as in claim 1 in which said reservoir has individual tanks and said connecting means joins one of said tanks to said first freezing platen and joins another of said tanks to said second freezing platen.
 4. A machine as in claim 1 in which said conduits connecting said refrigerant reservoir to said second freezing platen are flexible. 